It is well known to provide grid systems for suspending ceiling tiles, to form a suspended ceiling. Such systems commonly include two sets of runners or supports, positioned mutually perpendicularly. One set of mutually parallel supports is suspended from the building ceiling and a set of mutually parallel supports is fixed perpendicular to these. One of these sets of supports forms the support for the ceiling tiles. The invention is concerned with systems in which there are upper supports which are mutually parallel and are suspended from the building ceiling, and lower supports affixed to these upper supports and which are perpendicular to the upper supports, and which act as supports for the ceiling tiles.
In such a system it is critical that stability of the grid formed is maintained, in particular that the distance between the supports in each parallel set is consistent and is maintained. It is also important that a system be provided in which the ceiling tiles themselves are securely positioned and do not shift easily once installed.
It is desirable to provide a system in which installation is convenient. It is also desirable to provide a system which is economical to provide and operate. It is particularly desirable to achieve all of these objects in the context of a grid system in which the supports themselves are intended to be invisible from below.
Various systems are already known for suspending ceiling tiles, including those where the support grid is concealed by the tiles.
One such system is available from USG, under the trade name DONN VM-DX. In this system one mutually parallel set of upper supports is suspended from the building ceiling and a second mutually parallel set of lower supports, perpendicular to the upper set, is provided on which the ceiling tiles are supported. A clip system is provided which fixes the lower set of supports to the upper set of supports. This clip system can only be affixed to the upper supports by means of a screw or other fastening element passed through the mounting clip and the upper support. Consequently this is rather difficult and time consuming to install. Furthermore, the rigidity of the grid system thus provided is not as good as would be desired.
A further commercially available system is the Focus D system, available from Ecophon. This is slightly different, in that a mutually parallel set of supports is suspended from the building ceiling, and it is these supports which support the ceiling tiles. Mutual separation is maintained between these supports by the use of V-profiles as upper runners which maintain the spacing between the supports. A fastening means is provided to maintain the V-profiles in position relative to the lower supports. A similar system is described in EP-A-1154088.
This system has the disadvantage of being rather time consuming and complicated to install and requires two different types of runner.
JP-A-55/138536 discloses a system which concerns provision of false ceilings, and involves mutually perpendicular upper and lower runners. The runners do not contain any apertures.